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Delayed Self-Fertilization in Triodanis perfoliata

Self-fertilization is a reproductive technique that allows a plant to produce offspring even when pollinators may be scarce. Utilizing the process of delayed selfing, a species is with the benefits of both cross-pollination and self-fertilization as it has the opportunity to cross-fertilize early on in the flowers life and self-fertilize in the later stages. Research conducted on Triodanis perfoliata, a winter annual species, was designed to determine the timing of self-fertilization. Additionally, the study shed light on the species' ability to produce a full seed set through self-fertilization. Plants used in these experiments were grown from seeds collected from two populations: a wooded roadside in Pitt County, NC (arboretum population) and a disturbed grassy area in New Bern, Onslow County, NC (New Bern population). The plants were grown in standard potting medium containers with subirrigation and inspected every day for flower opening. Styles of various ages were collected (after flower opening) and placed in a solution. The pollen tubes that penetrated the stigma and entered into the style were counted. This helped determine that self-fertilization usually occurs towards the late stages of anthesis. / After the application of four treatments to randomly selected flowers, seed set count among the Triodanis perfoliata populations was compared. The first two treatments both included hand self-pollination on the first day of the female phase; however in one treatment the style was cut to prevent selfing late in anthesis while the style in the other treatment remained uncut. In the third and fourth treatments no hand-pollination was applied but once again in one treatment the style was cut off and remained intact in the other. Comparing the unpollinated treatments with the cut and uncut style confirmed that self-pollination did occur in late anthesis. The lower seed production within the cut style treatment indicated that selfing is at least somewhat delayed. Furthermore, the treatments comparing the cut and uncut style indicated that the removal of the style only prevented delayed selfing and had no additional effects on the experiment. The third experiment illustrated the relationship between pollination of stigma lobes and senescence of the flower. The timing between the two indicated early cross-pollination triggered senescence of the flower, preventing self-fertilization from occurring. However, if cross-pollination was not to occur early on, the flower would live a longer life, awaiting the chance to self-pollinate. Together, this research suggests that Triodanis perfoliata uses delayed selfing to reproduce.